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Swap Wiring, merging harnesses MORE MYSTERIES


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14 replies to this topic

#1 garner

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Posted 06 May 2004 - 02:39 PM

Hey all,

my brat is getting closer and closer to running!!! I have sorted ou the majority of the wiring issues but have one simple thing that I am unsure of.

here is the set up: brat harness runs lights, accesories, etc, EA82T harness and brain run the engine.

question: how do I tie the ignition in to the EA82T harness?

I can't find anything that seems like the ignition connector on the EA82 harnesss. Anybody know what the ignition switch connectors look like, color, wire # and color

help, my brain hurts...

garner

#2 Dr. RX

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Posted 06 May 2004 - 03:23 PM

One of the biggest problems with conversions is the wiring. I would try to use as much of teh EA82 wiring harness as possible. If you know what year of vehicle the EA82T came out of, you should get a FSM for that year and look up the wiring section, that should be a big help. You may have to splice wires from one harness onto wires of the other to get them to work. I usually get all that stuff together before I start a conversion like this, but even then sometimes it gets very confusing.

#3 garner

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Posted 06 May 2004 - 03:50 PM

yes, wiring, arrrggg.

the ea82t is from an 85. I have an FSM for that year but honestly, chiltons has better wiring diagrams. In the FSM, everything is there but no wire colors are specified and none of the control connectors are indicated. Very thourough in the emmisions/fuel injection area. full pin outs diagrams, etc.

I am fairly confident in most of what I've done to this point but I am hung up on tying in the ignition switch to power up the brain and engine control/sensors of the EA82t harness.

At this point, I can turn the key on, have lights, heater blower, etc. as well as turn over the starter!!! I just am un certain where the EA82T harness gets it's juice. I am assuming it only gets energized in the "ON" possition of the ignition switch.

Any help in finding the point in the EA82T harness that I should switch when I turn on the ignition????

#4 archemitis

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Posted 06 May 2004 - 04:20 PM

ok, i just looked under the hood of my hatch, that has the same efi as you have. the colors are never right, with these diagrams. i saw 3 different colors for the ig pulse signal. the ig pulse that goes to the negative of the coil, is shielded, with black plastic, with a white stripe, and wrapped in braided stell cable, then the wire under that is yellow(on mine). thats how the injectors know how to open.

the disty wires go to the same place they did stock. and i used the stock power and ground off of the ea81, to the coil.

then i wired in the fuel pump relay, very important to do this one stock. and dont put a high pressure pump under the hood, because it sucks the stock carb pump dry, and you run out of fuel.

give power to the main red wire(fat one) and a few others.

the starter signal wire is imprtant too. just stick that to the stock wire going to the starter solenoid.

you can plug your ea81 sensor wires into the oil sender, and the temp sender for the guage, and they work. same with the tach.

lotsa fun, dont know how i ever figured it out, considering you cant believe any of the colors you see, and the connectors on my diagram were all bogus too.

i just used the motor part of the harness, going from the manifold, to the computer, and figured out the rest on my own.
let me just say, its worth it! even without a turbo(yet)

#5 garner

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Posted 06 May 2004 - 04:37 PM

thanks for taking a look for me, the wires you called aout are really similar to what I've got going on so that makes me fell better.

I should have been more specific though.

I'm trying to figure out the ignition SWITCH, and how to tie the 2 harnesses together so that turning the key energizes the brain and motor harness, fp relay, ig relay etc...

garner

#6 archemitis

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Posted 06 May 2004 - 06:47 PM

that is basically an on off for the computer. i put mine on a switch, so i flip the computer on and off. and the main power stays powered all the time so it stores codes. give the correct wire 12 volts from the stock ginition relay, and it will work right off the key!

#7 garner

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Posted 06 May 2004 - 07:05 PM

so the brain should have one "on at all times" and one "on at ignition on" power input....

makes sense...I forgot about the code storage issue....

trouble code 666 (oddball incompatible engine and ecu swap)

so the ignition relay switches the computer on and off or does the computer switch the ignition relay????

#8 garner

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Posted 14 May 2004 - 02:01 PM

Help!!!!

I have sorted a few things out with my wiring issues but still ahve one significant problem. I am not getting my FP or IG relays to switch.

I found the EA82T harness ignition switch connector and tied the wires into the Brat harness, triple checked this and I am confident it is wired up properly.

Are these relays using low voltage or amprage to switch high or using high to switch low?

I have power to the high(larger diameter wire (RED)) side at all times. but as far as I can tell, no power to the low (small wire) side. I am assuming it's the low side that is switching the high side on and off....

questions:

Is there anything about using a AT harness with a MT tranny that could cause difficulties?

Does the AT inhibit switch do anything beyond not allowing you to turn the starter on without the car in Neutral?

What does F/ICCD stand for (Fuel/Ignition control computer device?)


Anyone have any ideas???

#9 archemitis

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Posted 14 May 2004 - 02:25 PM

try this. hook that fuel pump relay up like the book says, then feed power to the wire labeled ig power supply, without a relay, just right off the battery. that should be the on/off wire for the computer. also, keep the stock power wire that fed juice to the brat coil. it will give power to everything on that side of the coil.

#10 archemitis

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Posted 14 May 2004 - 02:29 PM

there are a buncha grounds that need to be bolted down too. pretty much any black one, if i remember right. i think i have 6 stacked on one bolt on the firewall

#11 garner

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Posted 14 May 2004 - 02:38 PM

intresting, I'll try that fuel pump wiring plan tonight.

I do have power to the + side of the coil when ignition is set to on. I thought that was a good sign....

Yep, I have about 6-8 grounds stacked up on the firewall too. I might check the ground off the computer and add another to be sure it is grounding. Cars are funny with grounds when you're more used to 120 volt electrical. I keep forgeting that the car is the ground...

keep em coming...(suggestions that is)

#12 garner

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Posted 20 May 2004 - 05:21 PM

Ok status update,

I don't remember exactly how I did it but here I am....

From what I can tell, everything works. Ignition relay switched, fuel pump runs! The computer is talking to me!!! I'm getting trouble codes for the AF meter (not hooked up), O2 sensor (not hooked up) etc. Whoooo Hooooo

My current mysteries are this:

In tracing out the harness, I found two connectors (round with 2 wires each) one I labled "Boost switch" the other I labled "Pressure switch"

I have no doo-dads which will fit the connectors nor do I have a clue what the boost switch or pressure switch look like?

Anybody have any ideas?

I can't wait to get this thing running, so close.....

garner

#13 garner

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Posted 21 May 2004 - 12:10 PM

Bump

Certainly someone knows something about the boost switch and pressure switch????

#14 calebz

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Posted 21 May 2004 - 12:28 PM

The boost switxh and pressuse switch were originally located right in front of the passenger side strut tower on your donor car. one of them controls the bosst light on the dash, one controls the fuel cutoff/overboost protection on the 86/86 turbo cars.

#15 garner

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Posted 21 May 2004 - 12:43 PM

Thanks calebz

so I can do with out the boost switch cause I will be using a boost gauge and don't need the boost light

How about the overboost cutoff switch, can I override that (I'll be using a boost controller of course) or is that a bad idea? If I can override, how?

So the overboost cutoff must tie into the wastegate hose or?....




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